Harmonic generator



Patented Oct. 25, i927.

tion Serial No..639,176, filed May '15, 1923, mental frequency generated by the sourcel UNirED STATES PATENT vorties.A

HERMAN A. AFFEL, F RIDGEWOOD, 'NEW JERSEY, l.ASSIGrN'OR T0 AMERIQAN" TELE- PHONE AN!)I TELEGRAPH COMPANY, A CORPORATION OF NEW YORK. i

Harmonic oninaznaroni.

This invention relates to high frequency generation and more particularly to the generation of high frequencies by. means of hal'- monic producers.' The present application is a division of applicants former appl1cafor -improvements in harmonic generators.

- y In carrier signaling systems it has, to some extent, been the practice to generate the c arA rier frequencies for the different signaling channels by a process of harmonic generai tions.

tion: Heretofore. this method has been used, however, only with relatively low harmonics. It is possible, however, to` obtain high harmonics by generating the high frequencies in a number of steps, that is, by

generating first a relatively low harmonic 1n one distorting device, such as a vacuum tube, for example, and successively multiplying the frequency thus produced by passing 1t through other tandem distorting circuits. n

. 1n accordance with the present invention it is proposed'to attain this successive or cascade generation of harmonics by means of a feed-back circuit so that only one distorting device or'tube` may be needed to effect the successive frequency transforma- It should be noted that a. feed-back circuit of this type dilfers from the ordinary feed-back circuit in that -a Adifferent frequency from the frequency originally api plied to the tube is ledfrom the output to the input circuit so that no singing effect will result.

The invention may now be more fully understood from the following detailed de scription when read in connection with the accompanying drawing, Figure of which is a simplified circuit diagram illustrating one embodiment of the inventionand. Figs.

on. The source S is coupled to the input circuit of the distorting tube V1 through windings 10 and 11 of a transformer 13.`

The output circuit of the distorting tube 1s `coupled to an outgoing circuit O through Original application led May 15, 1923, Serial No. 639,176. Divided and this application filed. December seria1 No. 154,772.

windings 14 and 15y of a transformer 17. A third winding 16 of the transformer 17 is inductively related to the winding 14 and is connected in circuit .with a plurality of selecting circuits 18 and 19, ea'ch tuned to a desired harmonic frequency of the vfunda- The selecting circuits 18 and 19 are coupled to the input circuit of a vacuum tube distorting device V2' through and 2l ofr a transformer 22. The vacuum tube device V2 is similar to the device V1 already described. The output circuit of the4 distorting tube V2 is coupled through windings 28 and 24 of a transformer 25 to another group of selecting ycircuits 26 and 27,

each tuned to suitable harmonics of the fundamental frequency These selecting cirwindings 20 cuits arel coupled to the input circuit of the v1ce of various harmonic frequencies of the fundamental frequency, among which the second harmonic 2f will be prominent. The second harmonic '2f will be transmitted directly to the outgoing circuit O and will also be transmitted through the winding 16 to the tuned circuit 18. The latter, by reason of its coupling to Athe input circuit of the distorting device V2 will transmit thev fre#A `quency -2]" to said distorting device so that the second harmonic of this frequency, or 4f, will appear in the output circuit thereof. The, frequency 4f will in turn be selected by the tuned circuit 26 and transmitted through the transformer 13 to the input circuit of the original distorting device V1. The latter will in turn produce in its output circuit, the second harmonic frequency 8f of the frequency 4f. The harmonic frequency 8f will be transmitted directly to the outgoing circuit O and will also be trans .mitted through the selective circuit 19 to the distorting device V2, which produces a second harmonic (lf) of the frequency 8f.

The frequency 16f is selected by the tuned circuit`27 and impressed upon the input circuit of the original distorting device V1 `so that the second harmonic of the frequency 16], or a frequency-32'f-, will be impressed' upon they outgoing circuit In addition to the frequencies ralready mentioned as being transmitted `directly to the outgoing circuit O, :itis apparent that all of the fundamental frequencies impressed upon the input circuit of the vacuum tube V1 will also appear in the output circuitso f that the frequencies f, 4f and lf will be directly transmitted to the outgoing circuit O in addition to the harmonics noted. Also it will be lapparent that since the distorting tubes are, in effect, modulating devices, all ofthe frequencies impressed upon the dis- 'I` torting device V1 will modulate each other feo to reduce sum and difference frequencies .as .wel as harmonics, and these sum and difference frequencies may be transmittedy directly to the outgoingcircuit O. `As a consequence, practically any harmonic of the fundamental frequency f may be obtained 1n the outgoing circuit O and, by providing suitable selective ldevices in the outgoing circuit 0, any7 desired harmonic may be segregated for any purpose desired.

y It will be observed that `the system above described provides for the recurrent trans- 'missionof energy through a circular path,

4the energy being translated in frequency at each successive stage of its transmission through the path.

A modied arrangement for attaining the results above outlined is illustrated in Fig.

. 2.v In this case, a balanced vacuum tube circuit involving the tubes-V1 and V2 1s employed, the circuit being of a well known type so arranged that the amplication comonentv may be suppressed and the double equencies transmitted. v The' alternating current source S is coupled to the input cir- `cuit'of 'thebalanced vacuum tube arrangement through windings 30 and 31 of a transformer w32.. The output circuit of the balanced vacuum tube arrangement is provided lwith a Winding 34 of a transformer 35 in the common branch of said output circuit and thewindi'ng 34 is inductively related to a winding 36 associated with a series of tuned selecting circuits 38, 39- and 40, 'each tuned to particular harmonics of the fundamental vfrequency f. The tuned circuits 38, 39 and 40 are coupled to the input circuit of the balanced Vacuum tube arrangement through the winding 33 inductively related to the winding 31 of the transformer 32.' If desire'fl, anl additional tube Vafmay be associated with the output circuit of the distorting tube 'arrangement V1, V2 through a winding 37 inductively related to the winding 34. The tube V3 may be utilized either to amplify frequencies transmitted thereto '65" or to. modulate together a plurality of frequencies' transmitted thereto, thereby pro- Lies'efiae ducing sum and difference frequencies vof such individual frequencies.

The operation is as follows: f, upon being impressed upon the distorting tubesVl and V2 produces in the Acommon output branch including the winding 34, even harmonics of the frequency f. rllhe odd The frequency i harmonics including the fundamental f will l be suppressed. The lsecond harmonic 2f will be transmitted through the 'windings 34 and 36 to the tuned circuit 33 and in turn will be transmitted .from the tuned circuit 38 through the windings 33 and 3l tothe input circuit of the balanced distorting arrange ment. r1his will result in thel production of a frequency 4f in the output circuit, which will be selected by the tuned circuit 39 and impressed upon the input circuit of the distorting tubes V1' and V2. The second harmonlc (8f) of this frequency will appear in the outputand will .be selected by circuit 40 to be applied to'tubes V1 and V2, so that finally a frequency lG/f will be produced and transmitted through the windings 34 and 37 to the input circuit of the vacuum tube V3.

The other frequencies generated in the winding 34 such, for example, as the frequencies 2f,`4f and-8f, will also be impressed upon the input circuit of the tube V3. If the tube V3-is adjusted to operate as an amplifier these frequencies will he' amplified directly and may beselected individually into suiti able circuits for anyA purpose desired. If,

however, the tube V3 be adjusted to operate'v as a modulator it will produce frequencies fcorresponding 4to the sums and differences between the several frequencies impressed upon its input lcircuit so that i'n the output circuit there will -appear frequencies corre- Isponding to these sums and differences, as

well as to the several harmonics ,already referred to.

It will be noted thaty by reason of the baltake place at any frequency since any fre-- quency transmitted to the -input circuit will be balanced out in .the output circuit and not be transmitted back to the input circuit. l

A circuit arrangement such as that above described is peculiarly advantageous as it enables the production of any high frequency. desired from a very low fundamental frequency.- Thus, a tuning fork, for example,

may be used to control the generation of a low fundamental frequency `which will be 'very accurately determined and the corrcsponding harmonics of the fundamental frequency will be likewise accurately fixed with respect to frequency. A circuit arrangement Lemaireillustrating this principle is shown in Fi 3, in which the tuning fork F is magnetically associated with U-shaped cores 50 and 51, so that the tincs of the fork form a path for the flux passing from one leg'of the U to the other. The input winding 31 of a balanced distorting tube arrangement V1, V2, such as that illustrated in Fig. 2, is wound upon the core 50, while windngs 52 and 53, lo includedin the individual branches of the plate circuits of the balanced arrangement` are wound upon the core 51. A winding 34, included in the common branch of the output circuit, is wound upon a core 54:, having inductively associated therewith a winding 37 included in an outgoing circuit O. The core 1 54 also includes windings 36, 36 and 3 6 associated with tuned circuits 38, 39 and 40. Each of the tuned circuits just referred to 2U includes an individual winding upon the core 50, as indicated at 33, 33 and 33.

The operation is as follows: Assuming Vthat the tuning fork F Iis set into vibration so that the tines of the fork vibrate alter- V95 nately toward and away from each other at and the odd harmonics being balanced therefrom, while the odd harmonics flow through the windings 52 and 53, the even harmonics being'prevented from flowing through these windings by the balanced arrangement of the circuit. ,The fundamental frequency f will consequently appear in the windin s 52 and 53, thereby producing changes in t e flux in the core 51 and causing the tinesof the tuning fork F to vibrate in correspondence therewith. As a consequence, the tuning fork F, once set in vibration, continues to vibrate owing to the mechanical feed-back connection between the output and the input circuits through the cores 51 and 50 and the tuningl fork The second harmonic 2f, flowing through the winding 34, will be transmitted through the winding 36 to the tuned circuit 38 and impressed through windings 33 and 31 upon the input circuit of the balanced distorting device, thereb producing a frequency 4f in winding 34 o the output circuit. This fre? quency is in turn selected by the circuit 39 and impressed upon the input circuit to pro-- duce a frequency 8f, which in its turn is also fed back to the input circuit, finally pro ducing a frequency 167s in the winding 34.-

As a consequence, the several even harmonic frequencies referred-to will be transmitted 6 `through the coupling' of windings 34 and 37 to the outgoing circuit -O and may beyutilized in any desired manner. Y

Instead of using vacuum tube devices for distorting purposes, as illustrated in Fig. 2, any type of rectifying device may be used, as indicated at Rl andR2 of Fig. et. It will I be noted that in this figure the winding'34 is included in a common branch of the balanced circuit arrangement so that only even harmonics will flow through this winding 7 and the fundamental or any otherfrequency impressed upon the Winding 31'cannot be fed backto said winding through the transformer windings 34 and 36. The fundamental frequency f is generated by a me'- chanically operated tuning `fork T, the tuning fork being actuated by a magnetMinf cluded in circuit with the winding 30 of transformer 32, a suitable source of current and an interrupting or resistance changing it device B .mechanically actuated by the tine of the tuning fork. The tuning fork isthus arranged to automatically control the energization of the magnet M so that its 'action Will becontinuous tosupply a periodically variable current to the winding 30. l

The operation will, of course, beobvious. The rectifying devices R1 and R2 distort the frequency impressed upon the winding 31 to produce harmonics and the second harmonic is'selectedbythe tuned circuit 38 and impressed upon the input winding 31. The second harmonic of this frequency in turn appears in the output circuit and is selected by the circuit 39 and impressed upon the in- WU put winding 31.` Finally, the second harmonic of this frequency (8f) is produced in the outputcircuit and selected by the circuit 40. The frequency 8f isv then transmitted from the circuit 40 through the transformer 105 6() to the outgoing circuit O..

It will be obvious that the general principles herein disclosed may be embodied in many other organizations widely different from those illustrated without departing from the spirit of the-invention as defined in the following claims.-

What is claimed is '4 1. A translating system including a plurality of translating devices, e'achhaving in- 115 put and output circuits, said devices being p so arranged that the output .of each tran 'mits to the input of the other, means to irn-I press electrical waves upon one of said trans` lating devices for transmission successively through said translatingdevices a number of times and means to produce a change in: frequency each time the Awaves are passed through a translating device.

2. A translating system including a 4plu-125 rality of'vacuum tube translating devices, each having inpntand output circuits, said devices being so arranged that the output of each transmits to the input of` the tether,

`means to impress electrical waves unon one fmt? l io ` meansto interconnect the output circuit of each translating device with the input'circuit of the other translating device comprising a plurality of selective circuits, means to produce a change in frequency each time electrical Waves are transmitted'tlirough atranslating device, said-selective circuits 0p'- to transmit the changed frequency to the in ut of the next translating device in -its vorr er so 'that the Waves pass through the translating devices 'successively a num- -ber of times and are changed in frequency each time.

4. A translating system' including a pair of vacuum tube translating devices, each having input and output circuits, means to impress electrical Waves on one of said vacuu m tube translating devices, means to interconnect the output circuit of each vacuum tube translating devicev with the input circuit of the othervacuum tube translating device' comprising a plurality of selective circuits, meansv to produce a change in frequency each time electrical Waves are trans- `mitted through a vacuum tubetranslating device, said selective cicuits operating to transmit the changed frequency -to the input of theneXt vacuum tube translating device in its order so that the waves pass through the vacuum tube translating devices successively a numberof times and are changed in frequencyeach time. e

In testimony whereof, I have signed. my name to this specificationv this 11th day of December, 1926. L

` HERMAN A. AFFEL.' 

